I have a Scanner Antennna that goes with my Pro Scanner that I use for listening to Train Activity along the mainlines and shortlines and I have two question I would like to ask. First question is, How far of a frequency can this Antenna, below in the picture, go before it loses it’s signal? My second and last question is, Is the magnet on the base of the Antenna strong enough in that if I’m going down the Freeway at 65 MPH in my pickup truck and I put this Antenna on the roof of my pickup truck, will it stay down without blowing over or blowing away by the high winds going along down the road at high speeds? If your curious about how high the antenna is, it’s about 3 foot high and the base is about 3 inches wide. I hope the picturers below help.
That’s a multiband antenna. Looks like the same one I have, and I’ve had good luck with it. I’ve also had pretty good luck with it over the road at “normal” Interstate speeds (70-75).
Range is subjective - there are so many factors that one can’t put a specific mileage on it. As I said, though, I’ve had good luck with mine.
I picked up the Railcom antenna with a mag base and am receiving up to 20 miles from locomotives. Base transmissions from CN are easily pulled in from 40 miles out. Ditto UP in Chicago.
My experience with a mag base rooftop antenna is it stays on a steel car roof at speeds of 65 - 70 mph. As to the ability of the antenna to pull in a signal a lot depends on the location and the strength of the signal.
My final question is, How do I get the Antenna Wire from the top of my Truck to the inside where my Scanner is? Do I go through the closed window or something else. If I have the wire on the top of the automatic windows and close them on the Antenna Wire would that effect it? The reason I ask these questions is because I haven’t done this and I think it would be easier then hauling it inside my pickup truck like I always do to Railfan.
Putting the antenna on the roof will increase the range, as the higher the antenna the better. I wouldn’t run the coax cable through the window, as it will crush the window gasket over time and cause leaks during rain. I route the coax through the door, finding a place where the coax will be cushioned by the foam rubber gaskets and not pinched by metal. I move it every few days, to slow down the formation of leaks.
When I used a mag. mount on my pick up, I ran the wire down between the cab and the bed then over to the passenger door (which I seldom used). I ran the wire through the bottom of the door so any gap in the door gasket would be less likely to allow water to drip in to the interior.
One thing I have done with my SUV. I found an old tie plate (discarded, not in use). I keep it in the rear of my SUV and mount the mag on it while driving. The reception is not as good obviously, but it is better than the small antenna.
I dont feel real comfortable driving with it outside yet.
I lead the antenna cable in through one of the doors near the top of the door, and I make sure the cable lies between the door and the frame gaskets so the wire doesn’t get pinched. I also place a plastic bag between the antenna’s mag base and the car’s roof to prevent the roof from being scratched when the antenna is installed or removed. Placing the bag between the roof and the antenna’s mag base doesn’t interfere with the ability of the mag base to hold on to the car’s roof even at 65 - 70 mph.
The antenna won’t ground through the paint. If you do a permanent mount, yes, but not through the paint with a mag mount.
I also run the cable down as low as I can and bring it in through the bottom of the door on the passenger side of my truck.
The semi-permanently mounted antenna for my fire department radio is mounted on a specially made bracket that comes out in the crack between the hood and fender. The cable is routed inside the truck out of sight.
There are cellular-look VHF-Hi antennas that mount on the glass, but I’m not sure of their efficiency.
The antenna base does not need to be in electrical (DC) contact with the metal of the vehicle. At the VHF frequencies in use, the capacitance between the antenna base and car is so great that the antenna appears shorted to the car’s metal. As for coverage, VHF signals are strong enough to reach from Minneapolis to Denver. What limits your reception is the curvature of the earth and atmospheric conditions that bend the radio waves. You can stretch the reception distance slightly, by a bigger antenna but once you reach the horizon of the sending radio, the signals go right over you. A rough estimate of the distance in miles to the horizon is the square root of 1.5 times the height in feet. If the locomotive is 15 feet tall its horizon is 4.7 miles. Your car antenna is 8 feet high so its horizon is 3.5 miles. Once you are 8.2 miles from the locomotive (assuming perfectly flat ground) the signal passes over your antenna. Antennas have very little to do with VHF reception. You can see now why the railroad puts their base stations on 50 foot towers (whose horizon is 9.6 miles added to the locomotive’s 4.7 miles gives a range of 14.3 miles) or on the top of hills. As for scanning, raise your antenna as high as possible. In the Twin Cities, the base stations for BNSF are on high towers on high hills and we can hear the dispatcher easily. Only when near the yards are we able to hear the locomotives and the hand held radios, unless we are up in a high rise.
